/*
 * Copyright 2011 Daniel Krieg
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package com.google.code.csf;

public class ServiceTemplate<ServiceType> {
    private ServiceLocator<ServiceType> serviceLocator;
    private Class<ServiceType> typeToLocate;

    public void setServiceLocator(ServiceLocator<ServiceType> serviceLocator) {
        this.serviceLocator = serviceLocator;
    }

    public void setTypeToLocate(Class<ServiceType> typeToLocate) {
        this.typeToLocate = typeToLocate;
    }

    public <ResponseType> ResponseType execute(ServiceAdapter<ResponseType, ServiceType> serviceAdapter) throws ServiceException {
        assert serviceLocator != null && typeToLocate != null && serviceAdapter != null;
        ServiceType service = null;
        try {
            service = serviceLocator.locate(typeToLocate);
            if (service == null) {
                throw new ServiceException("Failed to locate service of type " + typeToLocate.getName());
            }
            return serviceAdapter.with(service);
        } catch (ServiceException e) {
            throw e;
        } catch (Throwable throwable) {
            throw new ServiceException(throwable);
        } finally {
            if (service != null) {
                serviceLocator.release(service);
            }
        }
    }
}
